Electrosurgical apparatus for laparoscopic and like procedures

ABSTRACT

An electrosurgical instrument having a safety shield for use in laparoscopic or like electrosurgical procedures designed to receive a plurality of electrosurgical instrument inserts. The electrosurgical inserts are designed so as to provide quick and easy attachment to the electrosurgical apparatus while still providing enhanced resistance to rotation forces encountered during an electrosurgical procedure, and to distribute actuation forces occurring during use. The safety shield includes a crimped portion for transferring forces that occur during operation of an articulating instrument inserted therein to a handle assembly of the electrosurgical instrument. The electrosurgical instrument has a seal that reduces or prevents electrical current from flowing between the active electrode and shield assemblies. The electrosurgical instrument further includes a connector assembly for receiving a mating cable connector and providing a fail-safe interconnection therewith. A second preferred embodiment of the electrosurgical instrument is adapted to be removably connected with a replaceable shield/connector assembly through which the instrument is inserted. Furthermore, position of the shield with respect to the electrosurgical instrument can easily be accomplished.

BACKGROUND OF THE INVENTION

[0001] This invention relates to electrosurgical apparatus and inparticular to such apparatus for performing laparoscopic, pelvoscopic,arthroscopic, thoroscopic and the like surgical procedures. Proceduresof the foregoing type are experiencing explosive growth in thatincisions are kept to a minimum size and thus such procedures facilitateshorter hospital stays and lower costs., For example, with laparoscopicsurgery, a patient can return to normal activity within about one week,whereas with procedures where a large incision is made, about a monthfor full recovery may be required. It is to be understood thathereinafter and in the claims, whenever the term “laparoscopic” isemployed, similar procedures such as pelvoscopic, arthroscopic,thoroscopic, and the like where small incisions of the foregoing typeare made are also encompassed by this term.

[0002] Prior art electrosurgical laparoscopic apparatus typicallyinclude an active electrode probe that is removably insertable through atrocar sheath and that includes an electrode having an insulativecoating thereon. The tip of the probe may be of different conventionalshapes such as needle-shape, hook-shape, spatula-shape, graspers,scissors, etc. and serve various conventional functions such as suction,coagulation, irrigation, pressurized gas, cutting, etc. There are,however, various problems which may arise with respect to the use ofsuch a prior art apparatus when used in laparoscopic or like procedures.

[0003] A first problem may arise if the insulation on the activeelectrode is damaged thereby allowing active current (possibly in theform of arcing) to pass therethrough directly to the patient's tissue(possibly the bowel or colon) whereby peritonitis may set in withinseveral days. A second problem which can arise with prior art apparatusis caused by a capacitive effect where one electrode of the capacitanceis the active electrode and the other electrode of the capacitance is ametallic trocar sheath and the dielectric between these elements is theinsulation on the active electrode. Current from the active electrodewill be capacitively coupled to the trocar sheath and then returnedthrough the body and the return electrode to the generator. If thiscurrent becomes concentrated, for example, between the trocar sheath andan organ such as the bowel, the capacitive current can cause a burn tothe organ. A third potential problem occurs if the active electrodecontacts another instrument within the peritoneal cavity such asmetallic graspers or the like. The above-mentioned capacitive effectalso arises in this situation where the first electrode is the activeelectrode and the second electrode is the metallic graspers or the like.Thus, where the grippers contact a unintended site, injury may occur.

[0004] To solve some of the above identified problems, anelectrosurgical apparatus as disclosed in U.S. Pat. No. 5,312,401 toNewton et al. and assigned to the assignee of the present invention hasbeen proposed, the contents of which are incorporated herein byreference. Newton et al. disclose an electrosurgical apparatus thatincludes a safety shield that surrounds an active electrode and thatincludes insulation provided at least on the outer surface of the shieldand preferably also provided on the inner surface of the shield. Thesafety shield is connected to a return lead via a low impedance paththat includes monitoring circuitry used to detect the shield current anddetermine an abnormal condition therefrom.

[0005] In the event that the insulation on the active electrode isdamaged, current will pass through the damaged insulation to the shieldand then be returned to the return lead via the low impedance electricalconnection between the shield and the return lead of the electrosurgicalgenerator. A monitor circuit responsive to the shield currentdeactivates the electrosurgical generator whenever the shield currentcorresponds to an abnormal condition such as an insulation breakdown.The insulated shield of Newton et al. also addresses the second andthird above-mentioned problems by harmlessly returning any current whichis capacitively coupled to the shield to the return lead via theabove-mentioned low impedance connection.

[0006] Referring to FIG. 1 a cross-sectional view of an illustrativelaparoscopic apparatus in accordance with Newton et al. is shown. Atubular safety shield assembly 15 includes a tubular shield 9 having alayer of insulation 11 provided on the outer surface thereof and anoptional layer of insulation 13 provided on the inner surface thereof.The tubular shield assembly is inserted through trocar sheath 1 tothereby provide a passageway through which the active electrode probe 3may be inserted. An elongated port 23 may extend through the activeelectrode through which irrigation fluids, suction, a pressurized gasstream, etc. may pass. When active probe 3 and tubular shield assembly15 are in their respective inserted positions as shown in FIG. 1, theshield 9 surrounds the active probe from at least (a) a proximal point17 prior to the entry point 19 of the active probe into the trocarsheath 1 to (b) a distal point 21 in proximity to the tip 7 of theactive probe. Shield monitor circuitry 25 is connected to shield 9 via adual conductor lead 27 whereby the integrity of the connection of theshield to the monitor circuitry can be monitored.

[0007] The active electrode probe 3 is connected to an electrosurgicalgenerator 31 which may be of a conventional type via an active lead 35.The electrosurgical generator is connected to a patient return electrode37, preferably of the dual area type, via the shield monitor circuitry25 and, in particular, the return terminal of the generator is connectedto circuitry 25 via lead 29 while the circuitry 25 is connected to thereturn electrode via lead 33. Upon detection of a fault condition by theshield monitor circuitry, the electrosurgical generator 31 may bedeactivated by opening a relay in the connection between the generatorand patient return electrode 37 although other means may also beemployed to deactivate the generator.

[0008] Referring to FIG. 2 a generalized block diagram of the shieldmonitor circuitry 25 shown in FIG. 1 and used in Newton et al. is shown.A conductivity monitor 39 is connected to dual lead 27, the purpose ofthe conductivity monitor circuit being to measure the integrity of theconnection of lead 27 to shield 9. The dual connection provides aredundant path for shield monitoring current which is applied to lead 27as will be described in more detail hereinafter with respect to FIG. 9.A shield current sensor 41 senses the current passing from the shield 9to return electrode lead 29, 33 and may provide a signal voltageproportional to the instantaneous value of the shield current.

[0009] Measurement electronics circuitry 43 includes various circuitsfor measuring different parameters of at least the sensed shieldcurrent. The first of these circuits is a full bandwidth amplitudesensor circuit 47 which measures the amplitude of the full bandwidth ofthe sensed shield current. Processing and decision circuitry 53determines whether this amplitude exceeds a predetermined threshold and,if it does, a fault condition may be applied to indicators 61 over line55. Indicators 61 may be aural and/or visible and provide an appropriatealert. A data logger 73 may also be connected to processing and decisioncircuitry 53 to provide a hard copy of various safety conditions.

[0010] In addition to applying an alert signal over line 55, a generatordeactivate signal is applied over line 69 to a relay 71 which opens theconnection between return electrode 37 and generator 31 to thusdeactivate the generator and discontinue the application ofelectrosurgical energy. That is, the monitor circuitry 25, when usedoutside host electrosurgical generator 31, is preferably used with anelectrosurgical generator of the type having a dual return electrodelead whereby the integrity of the return electrode connection can bemonitored. Such monitoring circuitry is known whereby a split (ordouble) patient electrode is employed and a DC current (see GermanPatent No. 1139927 published Nov. 22, 1962) or an AC current (see U.S.Pat. Nos. 3,933,157 and 4,200,104) is passed between the splitelectrodes to sense patient contact resistance or impedance between thepatient and the electrodes. If an open circuit condition is sensed, thegenerator is deactivated. Since the relay 71 of FIG. 2 is opened upondetection of a fault condition, the return electrode connection is alsoopened to thus deactivate the generator. However, it is to be understoodother means will also occur to those skilled in this art fordeactivating the generator upon detection of a fault condition bymonitor circuitry 25.

[0011] Relative amplitude measurement circuitry 51 may be responsive tothe ratio of the amplitudes of the sensed shield current and the sensedreturn electrode current as determined by return current sensor 65.Processing and decision circuitry 53 determines whether this ratioexceeds a predetermined threshold and if it does an alert signal isapplied over line 55 while a deactivate signal is applied over line 69to relay 71 in a manner similar to that described above with respect tothe absolute amplitude fault condition.

[0012] Phase sensing circuitry 75 is responsive to the phase differencebetween the voltage applied to the active lead 35 of FIG. 1 and thesensed shield current. In FIG. 1 the monitor circuitry 25 is indicatedas being housed outside host electrosurgical generator 31. However, itmay also be incorporated within the electrosurgical generator. In thelatter instance, access may be readily gained to the active voltage andthus the phase comparison made by phase sensing circuitry 75 can bereadily effected. When the monitor is located outside of the hostelectrosurgical unit, it is somewhat more inconvenient to gain access tothe applied voltage signal; nonetheless, appropriate means will occur tothose of ordinary skill in the art to gain access to this signal.

[0013] Detection of the phase difference between the active voltage andthe shield current is a particularly good indicator of a faultcondition. That is, normal shield currents are exclusively capacitive—inparticular, due to the capacitive coupling between active electrode 5and shield 9, there is a 90° phase difference between the active voltageand the shield current under normal conditions. Hence, as long as theinsulation between the active electrode and the shield is intact, anormal condition will be sensed by phase sensing circuitry 75.

[0014] In general, the phase sensing circuitry, in response to the phasedifference between the applied inputs being 90°, provides a first output(high voltage, for example). If there is an insulation breakdown betweenthe active electrode 5 and the safety shield 9, arcing will typicallyoccur and such arcing currents are almost exclusively in phase with theapplied voltage. That is, the shield current will be in phase with theactive voltage. Phase sensing circuitry 75 detects this in phase, faultcondition to change the output from high to low.

[0015] Spectral sensing or filtered bandwidth circuitry 77 provides afurther reliable means for detecting the presence of arcing between theactive electrode and shield. Moreover, this method does not need accessto the active electrode voltage and thus readily lends itself to thosemonitor circuitry 25 which are located outside the host electrosurgicalgenerator 31. Spectral sensing circuitry is responsive to at least onepredetermined bandwidth of the sensed shield current to detect thepresence of a shield current produced by arcing where the arcing willtypically occur between the active electrode and the shield due toinsulation breakdown therebetween.

[0016] Both the phase sensing circuitry 75 and the spectral sensingcircuitry 77 also apply inputs to processing and decision circuitry 53in a manner similar to that described above with respect to circuits 47and 51 whereby the outputs of circuitry 75 and 77 may be utilized toactuate indicators 61 and data logger 73 and deactivate theelectrosurgical generator via relay 71. As indicated above, one or moreof the sensing circuits 47, 51, 75, and 77 may be independently utilizedor utilized in combination to effect the shield monitor function ofcircuitry 25.

[0017] Various measures have been taken in Newton et al. to render theoperation thereof fail-safe. For example, if the monitor circuitry 25 isemployed outside host electrical generator 31, there is a possibilitythe user may connect the return electrode directly into theelectrosurgical generator rather than through the monitor circuitry 25as illustrated in FIG. 1. If this occurs, the shield will not beconnected to the return electrode lead through a low impedance path, aswill be discussed below, and thus monitor circuitry 25 will be inhibitedfrom performing its monitoring function. To provide an alert to the userthat the return electrode has been inappropriately directly connected tothe generator 31, a shield to ground voltage sensor 49 may be provided,the sensor 49 being responsive to the shield voltage over line 45 vialead 27. The output of shield/ground voltage sensor 49 is applied toprocessing and decision circuitry 53 where an appropriate indicator 61is actuated if the return electrode is directly connected to theelectrosurgical generator.

[0018] If the return electrode is directly connected to theelectrosurgical generator, the voltage on the shield will rise to asubstantial percentage of the active voltage in view of an open circuitbetween the shield and the return electrode lead. Hence, whenever thevoltage on the shield exceeds a predetermined threshold, an appropriatesignal is applied to processing and decision circuitry 53 over line 57to thereby provide a desired alert.

[0019] Furthermore, when the monitor circuitry 25 is provided outsidehost electrical generator 31, it is desirable in some instances tobattery power the monitor circuitry 25. That is, if the monitorcircuitry is powered from an operating room electrical outlet, this willentail an additional wire being connected to the monitor circuitry wherein some instances it is desirable that the number of wires associatedwith the electrosurgical apparatus be reduced to a minimum. Accordingly,an activation control unit 59 may be employed which is responsive to thesensed shield current over line 63 or the sensed return current overline 67 to provide a battery power supply for the various circuits ofmonitor circuitry 25.

[0020] However, even with the use of the safety shield as disclosed inNewton et al., additional problems continue to exist when such anapparatus is used in a laparoscopic procedure or the like. Specifically,in order to facilitate sterilization and replacement of electrosurgicalinstruments, there is a demand for a shielded electrosurgical instrumentthat accepts a plurality of electrosurgical inserts (such as graspers,scissors, etc.) that can easily be removed and replaced. Furthermore,the is a need for such inserts to be reliably and securing attached tothe shielded electrosurgical instrument in order to prevent undesirableloosening during a surgical procedure. However, it is still desirablefor the electrosurgical insert to be easily removed to facilitatesterilization of the electrosurgical instrument.

[0021] Furthermore, potential problems exist with respect to theinterconnection between an electrosurgical generator and a shieldedelectrosurgical instrument. Although precautions to ensure properinterconnection to the shield of the electrosurgical instrument havebeen previously taken, there still exists a possibility that a falsesignal indicating proper interconnection could result. In such case, asurgeon could proceed under the false impression that shield monitor wasoperation when in fact it is not. Of course, in the event of aninsulation failure, the results could be catastrophic.

[0022] Furthermore, the structure of the connectors used to make aconnection between the active and shield electrodes of andelectrosurgical instrument and an electrosurgical generator and monitorare such that foreign matter, such a liquids encountered during thesurgical procedure, could invade the connector housing, thus creating anelectrical short circuit between the active electrode and the shieldelectrode of the electrosurgical instrument. Again, such a situation isundesirable when performing an electrosurgical procedure.

[0023] Also, inserts designed for use with electrosurgical instrumentsare such that a mechanical failure could occur during an electrosurgicalprocedure, thus rendering the electrosurgical instrument inoperative.Again, should such failure occur during a surgical procedure, danger tothe patient could result.

[0024] Furthermore, a need exists for an integral shield assemblyadapted for use with a plurality of electrosurgical instruments suchthat the electrosurgical instruments can be selectively interconnectedwith, and positioned with respect to, the shield assembly. This allowsseparation of the shield assembly and electrosurgical instrument to beeasily accomplished to facilitate sterilization of the instrument.Furthermore, replacement of defective or worn shield assemblies can beeasily accomplished with the provision of a standardized shield assemblysuitable for use with a plurality of electrosurgical instruments.

SUMMARY OF THE INVENTION

[0025] The present invention provides a solution to the above mentioned,and other, problems with prior electrosurgical apparatus andspecifically with prior shielded electrosurgical apparatus. Inaccordance with the present invention, an electrosurgical instrumenthaving a safety shield for use in laparoscopic or like electrosurgicalprocedures designed to receive a plurality of electrosurgical instrumentinserts is disclosed. The electrosurgical inserts are designed so as toprovide quick and easy attachment to the electrosurgical apparatus whilestill providing enhanced resistance to rotation forces encounteredduring an electrosurgical procedure, and to distribute actuation forcesoccurring during use. The safety shield includes a crimped portion fortransferring forces that occur during operation of an articulatinginstrument inserted therein to a handle assembly of the electrosurgicalinstrument. The electrosurgical instrument has a seal that reduces orprevents electrical current from flowing between the active electrodeand shield assemblies. The electrosurgical instrument further includes aconnector assembly for receiving a mating cable connector and forproviding a fail-safe interconnection that is sealed to preventbreakdown between a shield and active conductor of the instrument. Asecond preferred embodiment of the electrosurgical instrument is adaptedto be removably connected with a replaceable shield/connector assemblythrough which an electrosurgical insert is inserted. Furthermore,positioning of the shield with respect to the electrosurgical insert caneasily be accomplished.

[0026] In view of the forgoing, it is an object of the present inventionto provide an insert for an electrosurgical apparatus having a novelstructure that securely attaches the insert to the electrosurgicalapparatus.

[0027] It is another object of the present invention to provide aninsert for an electrosurgical apparatus having a novel structure thatpermits quick, easy and secure attachment of the insert to theelectrosurgical apparatus.

[0028] It is a still further object of the present invention to providean insert for an electrosurgical apparatus having a novel structure thatallows for quick and easy replacement of the insert in theelectrosurgical apparatus.

[0029] It is yet another object of the present invention to provide aninsert for an electrosurgical apparatus having a novel structure thatcan be quickly and easily attached to the electrosurgical apparatuswhile still providing enhanced resistance to rotation forces encounteredduring an electrosurgical procedure.

[0030] It is a further object of the present invention to provide aninsert for an electrosurgical apparatus having a novel interface withthe electrosurgical apparatus to redistribute actuation forces appliedon that insert during operation.

[0031] It is a further object of the present invention to provide aninsert for an electrosurgical apparatus having a protrusion that isreceived by the electrosurgical apparatus and that is used to actuatethe electrosurgical insert.

[0032] It is another object of the present invention to provide a shieldassembly for an electrosurgical instrument that provides a secureinterconnection between the shield and associated insulating layers, andthe instrument handle assembly to permit actuation force to be moredirectly transferred to the handle assembly.

[0033] It is still another object of the present invention to provide ashield assembly for an electrosurgical instrument that includes acrimped portion for transferring forces that occur during operation ofan articulating instrument inserted therein to a handle assembly of theelectrosurgical instrument.

[0034] It is a further object of the present invention to provide ashielded electrosurgical instrument having improved electricalinsulation between the active electrode and shield assemblies.

[0035] It is yet another object of the present invention to provide ashielded electrosurgical instrument having a seal that reduces orprevents electrical current from flowing between the active electrodeand shield assemblies.

[0036] It is another object of the present invention to prevent surfacebreakdown from occurring between an active electrode and a shield of anelectrosurgical instrument.

[0037] It is still another object of the present invention to provide anelectrosurgical instrument having an improved connector assembly adaptedto receive a connector for supplying electrosurgical active potentialand for providing interconnection with the electrosurgical instrumentshield.

[0038] It is another object of the present invention to provide anelectrosurgical instrument having an improved connector assemblydesigned to provide redundant contact points to a shield of theelectrosurgical instrument in order to provide for fail-safe operationof that instrument.

[0039] It is yet another object of the present invention to provide acord connector assembly for interconnecting to an electrosurgicalinstrument and constructed to provide a seal to prevent liquids andother foreign matter from entering the electrosurgical instrument duringa surgical procedure.

[0040] It is a still further object of the present invention to providean electrosurgical instrument comprising an integral shield assemblyadapted for use with a plurality of electrosurgical instruments suchthat the electrosurgical instruments can be selectively interconnectedwith, and positioned with respect to, the shield assembly.

[0041] It is an object of the present invention to provide anelectrosurgical instrument that includes an integralhandle/articulatable instrument assembly that is inserted through anintegral shield/connector assembly within the sterile field.

[0042] It is an object of the present invention to provide a shieldassembly for use with an electrosurgical instrument that can be easilyremoved and replaced in the event of damage or wear to the shieldassembly.

[0043] It is an object of the present invention to provide astandardized electrosurgical instrument having a plurality ofarticulating replaceable/disposable instruments thereon that is adaptedfor interconnection with a standard, replaceable and/or disposableshield assembly.

[0044] It is an object of the present invention to provide anelectrosurgical instrument having position means integrally formedtherewith to permit position of the electrosurgical instrument withrespect to a electrosurgical shield assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0045]FIG. 1 illustrates a cross-sectional view of a conventionalshielded electrosurgical instrument.

[0046]FIG. 2 illustrates a generalized block diagram of conventionalshield monitoring circuitry for use with the shielded electrosurgicalinstrument shown in FIG. 1.

[0047]FIG. 3 illustrates an articulated electrosurgical instrument inaccordance with the present invention.

[0048]FIG. 4 illustrates an enlarged view of an end of the tubularsafety shield assembly shown in FIG. 3.

[0049]FIG. 5 shows a further enlarged view of an end of the tubularsafety shield assembly shown in FIGS. 3 and 4.

[0050]FIG. 6 illustrates in further detail a portion of an end of thetubular safety shield assembly shown in FIG. 5.

[0051]FIG. 7 shows a schematic diagram illustrating the operation of ahousing and adapter as shown in FIGS. 4-6.

[0052]FIG. 8 shows an expanded view of the connector portion androtatable positioning means of the electrosurgical instrument shown inFIG. 3.

[0053]FIG. 9 illustrates a cross-sectional view of the connector portionshown in FIG. 8 taken along the lines A-A and B-B in FIG. 3.

[0054]FIG. 10 illustrates an enlarged view of a connector assembly usedin accordance with the present invention to interface with the connectorportion shown in FIGS. 8 and 9.

[0055]FIG. 11 illustrates a more detailed cross-sectional side view ofthe connector assembly shown in FIG. 10 taken along line 11-11.

[0056]FIG. 12 illustrates an alternative preferred embodiment of anelectrosurgical instrument in accordance with the present invention.

[0057]FIG. 13 illustrates an enlarged view of a shield portion of theelectrosurgical instrument shown in FIG. 12.

[0058]FIG. 14 illustrates an articulatable insert in accordance with thepresent invention suitable for use with the electrosurgical instrumentshown in FIG. 3.

[0059]FIG. 15 illustrates one design in accordance with the presentinvention for the articulatable insert shown in FIG. 14, and theinteraction with the trunnion shown in FIG. 3.

[0060]FIG. 16 illustrates an alternative design in accordance with thepresent invention for the articulatable insert shown in FIGS. 14 and 15,and the interaction with the trunnion shown in FIG. 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0061] Referring first to FIG. 3, an articulated electrosurgicalinstrument in accordance with the present invention is shown generallyat 10. As can be seen in FIG. 3, the articulated electrosurgicalinstrument 10 includes a handle assembly 12, a connector portion 14, anda rotatable positioning means 16 disposed at a first end of a tubularsafety shield assembly 18. Extending through tubular safety shieldassembly 18, is articulated insert 20 that includes articulatableinstrument 22 that is disposed at a second end 34 of tubular safetyshield assembly 18 as shown in FIG. 3. Although articulatable instrument22 is shown in FIG. 3 as a scissors, in accordance with the presentinvention, articulating instrument 22 could be any suitable instrumentincluding scissors, graspers, etc.

[0062] Handle assembly 12 includes stationary handle 24 and movablehandle 26 that is pivotally attached to stationary handle 24 at pivotpoint 28 by removable fastener 30. As described in more detail below inconnection with FIGS. 14-16, articulating insert 20 extends throughstationary handle 24 and removably attaches to a groove in trunnion 32.In this manner, by rotation of movable handle 26 with respect tostationary handle 24 around pivot point 28, articulatable insert 20 canbe operated as described below.

[0063] Articulatable insert 20 is inserted into articulatedelectrosurgical instrument 10 through second end 34 of tubular safetyshield assembly 18. Referring to FIG. 4, an enlarged view of second end34 of tubular safety shield assembly 18 is shown. As can be seen in FIG.4, tubular safety shield assembly 18 includes PEEK(Poly-ether-ether-ketone) tube 50, shield 52, inner shrink tube 54,outer shrink tube 56 and adapter 58. Although tube 50 is referred to asbeing made from PEEK material, any other suitable high temperatureinsulating material having sufficient structural rigidity could be usedinstead.

[0064] PEEK tube 50 provides the primary structural support for tubularsafety shield assembly 18 and servers to insulate articulatable insert20 from shield 52, which could be, for example, a stainless steel tube.As shown in FIG. 4, shield 52 extends to a point 60 that is in proximityto the end 62 of tubular safety shield assembly 18. Adjacent to shield52 and extending from point 60 to end 62 of tubular safety shieldassembly 18 is inner shrink tube 54 that serves to electrically isolateshield 52 from the exposed surface of articulating instrument 22. Outershrink tube 56 covers both shield 52 and inner shrink tube 54 and servesto provide additional electrical insulation between shield 52 and theexposed surface of articulating instrument 22. Furthermore, outer shrinktube 56 effectively prevents a conductive material from coming intocontact with both shield 52 and articulating instrument 22, therebycreating an electrical short circuit between the shield 52 andarticulating instrument 22. Articulating instrument 22 is connected toarticulatable insert 20 through appropriate linkages that permitsarticulatable instrument 22 to be operated by longitudinal motion ofarticulatable insert 20 through PEEK tube 50. The details of the linkagebetween articulatable instrument 22 and articulatable insert 20 areconventional and therefore not shown in further detail in FIG. 4.

[0065] Adapter 58 is provided in end 62 of tubular safety shieldassembly 18 to threadably receive articulatable insert 20. Adapter 58 isused in order to prevent damage from occurring to threads 64 in PEEKtube 50 from repeated attachment and removal of articulatable insert 20and is preferably made from a more durable material such as metal. Insuch case, it is important to note that inner shrink tube 54 and outershrink tube 56 further serve to electrically isolate shield 52 fromadapter 58, which in operation will selectively be maintained at anactive electrosurgical voltage potential.

[0066]FIG. 5 shows a further enlarged view of end 62 of tubular safetyshield assembly 18 that contains one particularly important feature ofthe present invention. For clarity, FIG. 5 includes end 62 of tubularsafety shield assembly 18 and adapter 58, but does not show inner shrinktube 54 or outer shrink tube 56, which would be positioned as shown inFIG. 4. As shown in FIG. 5, the connection between articulatableinstrument 22 and articulatable insert 20 is formed within housing 70made from a resilient material sufficient to allow for flexure when aforce is exerted at points F1 during insertion of articulatable insert20.

[0067] A further detail of the portion enclosed by circle 72 is shown inFIG. 6. As seen in FIG. 6, housing 70 preferably contacts adapter 58 atend 62 of tubular safety shield assembly 18. Furthermore, as describedin more detail below, housing 70 preferably contacts adapter 58 at apoint which is on the outer periphery of adapter 58 as shown in FIG. 6.Housing 70 is preferably formed substantially as shown in FIG. 6 so thathousing angle 74 between first surface 76 disposed substantiallyparallel to the longitudinal dimension of articulatable insert 20 andsecond surface 78 disposed substantially orthogonally to longitudinaldimension of articulatable insert 20 is less than 90°. Similarly,adapter angle 80 is preferably formed so that adapter angle 80 betweenfirst surface 82 disposed substantially parallel to the longitudinaldimension of articulatable insert 20 and second surface 84 disposedsubstantially orthogonally to longitudinal dimension of articulatableinsert 20 is less than 90°. Furthermore, it is most preferred thathousing angle 74 is less than adapter angle 80. By forming both housingangle 74 and adapter angle 80 less than 90° and by forming housing angle74 less than adapter angle 80, contact between adapter 58 and housing 70at the outer periphery of adapter 58 and housing 70 near end 62 isensured when articulatable insert 20 is secured into tubular safetyshield assembly 18.

[0068] The specific design of housing 70 and adapter 58 is such thatincreased frictional forces result when articulatable insert 20 issecured to adapter 58 as described below in connection with FIG. 7. Thisis desirable in order to increase the amount of rotational forcenecessary to disengage articulatable insert 20 from tubular safetyshield assembly 18 and ultimately from electrosurgical instrument 10.Without the structure shown in FIG. 6 and the associated increase inrotational force necessary to disengage articulatable insert 20,articulatable insert 20 could inadvertently be disengaged from tubularsafety shield assembly 18 during a surgical procedure. That is, should agiven surgical procedure require that a rotational force be applied toarticulating instrument 22, it is important that such force betransferred to the appropriate surgical location and not expendedthrough undesirable rotation between housing 70 (and thus articulatableinsert 20 and instrument 22) and adapter 58 (and thus tubular safetyshield assembly 18 and electrosurgical instrument 10). Additionally,articulatable insert 20 can easily be securing attached within thesterile field to the electrosurgical instrument during a surgicalprocedure.

[0069] Furthermore, as noted above, the most preferred structure ofhousing 70 and adapter 58 is such that contact occurs at the outerperiphery of housing 70 and adapter 58. This is ensured in the mostpreferred embodiment by the provision of housing angle 74 and adapterangle 80 both being less than 90° and housing angle 74 being less thanadapter angle 80. This is particularly advantageous in that the amountof force required to rotate articulatable insert with respect to tubularsafety shield assembly 18 is increased by having the contact pointdisposed on the outer periphery of housing 70. That is, if the contactpoint were disposed inward of the outer periphery, the resultingincrease in friction would be less than if the contact point were at theouter periphery as shown in FIG. 6.

[0070] Referring next to FIG. 7, a schematic diagram of the operation ofhousing 70 is shown to illustrate the manner in which the design ofhousing 70 and adapter 58 increase the rotational friction therebetween.As noted above, housing 70 is preferably made from a resilient materialsufficient to allow for flexure when a force is exerted at points F1shown in FIG. 5. When such force is exerted, housing 70 deflects from anat rest position 90, illustrated in FIG. 7 by dotted lines, to a flexedposition 92. Furthermore, when such flexure takes place, outer periphery94 of housing 70 is displaced by a distance 98 with respect to innerperiphery 96 of housing 70. Removal of force F1 from housing 70 causesthe housing to tend to return to at rest position 90.

[0071] From the above description and illustrations shown in FIGS. 5-7,it will be clear to one of skill in the art that the outer periphery ofsurface 78 of housing 70 near end 62 as shown in FIG. 6 can be laterallydisplaced away from the outer periphery of surface 84 of adapter 58 nearend 62 by exertion of force F1. With the release of force F1, surface 78will tend to laterally return toward adapter 58 and engage surface 84 ofadapter 58 at the outer periphery thereof. Accordingly, during insertionof articulatable insert 20 into tubular safety shield assembly 18, auser can provide force to housing 70 by squeezing the housing at thepoints indicated by F1. If this force is maintained until articulatableinsert 20 is seated in adapter 58, and then released, housing 70 willsecurely engage adapter 58 as described above and thereby increase therotational frictional force present between housing 70 and adapter 58.In this manner, one important object of the present invention—theprovision of an insert for an electrosurgical apparatus that quickly,easily and securely attaches to the electrosurgical apparatus and whichprovides enhanced resistance to rotational forces encountered during anelectrosurgical procedure—is realized.

[0072] Of course, although the above description focuses on adapter 58,it is within the scope of the present invention that adapter 58 not bepresent and that end 62 of tubular safety shield assembly 18 be designedto include angle 80 as shown in FIG. 6. In this manner, the sameincrease in rotational friction can be achieved without the provision ofadapter 58 if necessary.

[0073] Another important feature of articulatable insert 20 inaccordance with a further aspect of the present invention will next bediscussed in connection with FIGS. 14-16. FIG. 14 generally illustratesarticulatable insert 20 and includes threads 81 which securearticulatable insert 20 with adapter 58 provided in end 62 of tubularsafety shield assembly 18. Housing 70, for receiving any one of aplurality of articulatable instruments (not shown) is disposed at afirst end 83 of articulatable insert 20.

[0074] As noted above in connection with FIG. 3, articulating insert 20extends through stationary handle 24 and removably attaches to a groovein trunnion 32. In this manner, by rotation of movable handle 26 withrespect to stationary handle 24 around pivot point 28, articulatableinsert 20 can be operated.

[0075] Second end 85 of articulatable insert 20 illustrates a firststructure that could be used to interface with the groove in trunnion32, which is shown in more detail according to one preferred embodimentin FIGS. 15A-15D. FIG. 15A shows a top view of an illustrative trunnion32 according to the present invention. FIG. 15B shows a front view oftrunnion 32 shown in FIG. 15A. FIG. 15C shows a side view of trunnion 32shown in FIGS. 15A and 15B. Finally, FIG. 15D shows a top view oftrunnion 32 similar to FIG. 15A with the articulatable insert 20inserted therein. As can be seen in FIGS. 14 and 15A-15D, second end 85of articulatable insert 20 includes a turned down portion 86 and aretaining ball 87. In operation, turned down portion 86 will be insertedinto groove 88 in trunnion 32, and retaining ball 87 will cooperate withtrunnion 32 to allow the transfer of force from trunnion 32 toarticulatable insert 20.

[0076] FIGS. 16A-16D show a second preferred structure of trunnion 32and second end 85 of articulatable insert 20. Again, FIG. 16A shows atop view of trunnion 32 according to this second preferred embodiment,FIG. 16B shows a front view of trunnion 32 shown in FIG. 16A, FIG. 16Cshows a side view of trunnion 32 shown in FIGS. 16A and 16B, and FIG.16D shows a top view of trunnion 32 similar to FIG. 16A with thearticulatable insert 20 inserted therein. As can be seen in FIGS.16A-16D, trunnion 32 includes a notch 89 formed approximately in thecenter of groove 88 in trunnion 32, and articulatable insert 20 includesprotrusion 91. In operation, protrusion 91 is received in notch 89 toprovide addition cooperation between articulatable insert 20 andtrunnion 32. Accordingly, not only will force be transferred throughretaining ball 87 as in the embodiment shown in FIGS. 15A-15D, but alsothrough the interaction of protrusion 91 and notch 89.

[0077] In addition to distributing the force applied to articulatableinsert 20, protrusion 91 and notch 89 further operate as a fail-safe inthe event that retaining ball 87 on second end 85 of articulatableinsert 20 is damaged or otherwise becomes non-functional. In such asituation, protrusion 91 and notch 89 will still permit actuation ofarticulatable insert 20, which could be critical should the failure ofretaining ball 87 occur during a surgical procedure.

[0078]FIG. 8 shows an expanded cross-sectional view of connector portion14 and rotatable positioning means 16 as shown in FIG. 3 ofelectrosurgical instrument 10. As can be seen in FIG. 8, tubular safetyshield assembly 18 extends through means 16 and connector portion 14,including PEEK tube 50, shield 52 and outer shrink tube 56. Rotatablepositioning means 16 generally includes positioning knob 100, knoblocking nut 102, wedge 104 and detent 106. Connector portion 14generally includes connector housing 110, front seal 112, rear seal 114,ferrule 116, locking ring 118 and active contact electrode 120.

[0079] Positioning knob 100 is secured to tubular safety shield assembly18 through the combination of knob locking nut 102 and wedge 104. Knoblocking nut 102 is threadably secured to positioning knob 100 and actsto draw positioning knob 100 to cause a transverse force component to beexerted through wedge 104 to tubular safety shield assembly 18, thussecuring positioning knob 100 to tubular safety shield assembly 18.Furthermore, positioning knob 100 includes a plurality of indentedportions 122 circumferentially disposed on positioning knob 100 toreceive detent 106, which is biased toward positioning knob 100 byspring 124. In this manner, positioning knob 100, and thus tubularsafety shield assembly 18 and articulatable instrument 22, can berotatably positioned at any one of a plurality of positionscorresponding to one of indented portions 122 and releasably held inthat position by detent 106.

[0080] Referring next to connector portion 14, it can be seen that rearseal 114 abuts the rear portion 126 of connector housing 110 andsurrounds and is frictionally engaged with PEEK tube 50 and frictionallyengaged connector housing 110. In the most preferred embodiment, PEEKtube 50 is machined to a reduced diameter under rear seal 114 in orderto improve the surface tolerances and to ensure a uniform frictionalengagement between PEEK tube 50 and rear seal 114. That is, duringmanufacturing the tolerance on the diameter of the PEEK tube isapproximately +/−0.003 inches, while the tolerance that can be achievedfrom machining PEEK tube 50 is approximately +/−0.001 inches. Silicongrease is also applied to the interface of rear seal 114 with bothconnector housing 110 and PEEK tube 50 in order to seal any gaps leftafter rear seal 114 is engaged with PEEK tube 50. Rear seal 114 could bemade from any elastomeric electrically insulating material and in themost preferred embodiment is made from tetroflourethylene (TFE).

[0081] Rear seal 114 and its interface with PEEK tube 50 are importantto prevent an electrical creep path between shield 52 and active contactelectrode 120 from occurring. In operation, the active contact electrode120 of electrosurgical instrument 10 will typically be maintained at ahigher voltage potential than shield 52. As can be seen in FIG. 8, thisvoltage potential will be applied across rear seal 114. In view of thisvoltage potential, there will be a tendency for current to flow betweenactive contact electrode 120 and shield 52, generally along theinterface, or creep path, between rear seal 114 and PEEK tube 50. Suchcurrent flow, however, is undesirable since it could lead to a faultcondition (as a result of the voltage present on shield 52) and thesubsequent deactivation of the electrosurgical generator. Furthermore,should this creep current become too high, the active potentialapplication to the electrosurgical instrument could detrimentally beeffected.

[0082] In order to reduce this current flow, it is desirable to providea sufficiently tight, uniform frictional engagement between rear seal114 and PEEK tube 50. Furthermore, the application of silicon grease,which is also electrically insulating, will further serve to reduce anyelectrical current flow between active contact electrode 120 and shield52 along the interface of rear seal 114 and PEEK tube 50. Accordingly,this aspect of the present invention provides an electrosurgicalinstrument having improved electrical insulation between the active andshield electrodes.

[0083] Connector portion 14 further includes ferrule 116, which isattached to shield 52 and in the most preferred embodiment made frommetal or other conductive material. As described in more detail below inconnection with FIG. 9, ferrule 116 serves to provide an electricalconnection between shield 52 and an electrosurgical monitoringapparatus. Ferrule 116 also cooperates with retaining ring 118, which issnap fit into groove 128 in connector housing 110, to secure tubularsafety shield assembly 18 into connector housing 110. Finally, frontseal 112, which in the most preferred embodiment is made from TFE, isinserted into and frictionally engages connector housing 110 and tubularsafety shield assembly 18. Front seal 112 serves to prevent fluid, dirt,or other impurities from entering connector housing 110 and interferingwith the connection and operation of retaining ring 118 and ferrule 116.

[0084] Another important feature of the present invention shown in FIG.8 is crimp area 200. PEEK tube 50 has notch 202 circumferentiallydisposed therein and adapted to receive a portion of shield 52 and outerinsulating tube 56 that are crimped at a location corresponding to notch202. In this manner, shield 52 and outer insulating tube 56 are securelyinterconnected with PEEK tube 50 to form tubular safety shield assembly18. This feature is particularly important in that longitudinalactuation forces used to actuate articulating instrument 22 aretransmitted from the PEEK tube 50 to the shield 52 through this joint.This in turn transfers a portion of the actuation force to the handleassembly 12 through retaining ring 118, ferrule 116, front seal 112 andrear seal 114. The use of the crimp area 200 is particularly importantin permitting this transfer of force while still maintaining electricalisolation between the shield 52 and an articulating insert locationwithin tubular safety shield assembly 18.

[0085] Connector portion 14 is used to provide for electrical connectionto both shield 52 and active contact electrode 120, which in turnconnects to articulating insert 20 to provide electrosurgical potentialto the articulating instrument 22. FIG. 9 illustrates a cross sectionalview of connector portion 14 taken along the lines A-A and B-B shown inFIG. 3, and provides further details of the interconnection of shield 52with a cable leading to an external monitoring apparatus throughconnector assembly 300. As seen in FIG. 9, connector assembly 300removably attaches to connector housing 110. Connector assembly 300preferably includes two contact pins 212 which are received, along withpin insulator 213, in contact holes 214 in connector housing 110.

[0086] As can be seen in FIG. 9, connector housing 110 includes contactspring 210, which biases contact pins 212 toward and into contact withferrule 116. In addition, contact spring 210 makes contact with ferrule116 at point 216 near the bottom of connector housing 110. Thisadditional contact point ensures that electrical connection betweencontact pins 212 and ferrule 116 (and thus shield 52) is made. As notedin U.S. Pat. No. 5,312,401 to Newton et al. discussed above,electrosurgical monitoring circuitry detects an electricalinterconnection between contact pins 212 in order to determine thatconnector assembly 300 is properly connected to connector housing 110.That is, if electrical conduction between connector pins 212 isdetected, typically as a result of interconnection with ferrule 116 andthus shield 52, then proper connection is indicated.

[0087] However, a false indication of proper interconnection couldresult in the situation where contact pins 212 each come into contactwith contact spring 210, but fail to contact ferrule 116. Thus, byvirtue of the electrical interconnection through contact spring 210 aproper interconnection would incorrectly be indicated. Accordingly, byproviding contact point 216 between ferrule 116 and contact spring 210,should this situation occur, electrical contact between contact pins 212and shield 52 will still result. Thus, the provision of contact point216 is particularly advantageous in preventing a false indication thatthe shield monitoring circuitry is properly connected, which couldresult in injury to a patient in an electrosurgical procedure.

[0088] Referring next to FIG. 10, an enlarged view of connector assembly300 is shown. As seen in FIG. 10, connector assembly 300 is formed fromplug shells 302, 304 and plug floor 306. Plug shells 302, 304 are heldtogether and to plug floor 306 by screw 308, which extends through plugshell 302, plug floor 306 and is threadably engaged with plug shell 304to thereby secure plug shells 302, 304 and plug floor 306 together.

[0089] Strain relief 305 is provided to reduce the strain on wire 307,which is received by connector assembly 300 to provide electricalcontact between connector assembly 300 and electrosurgicalgenerator/monitoring circuitry. Also shown in FIG. 10 are shield contactpins 212 and active contact 310, which serves to connect an activeelectrosurgical potential received from an electrosurgical generator toelectrosurgical instrument 22 through active contact electrode 120,shown in FIG. 8. Also, insulator cups 312 can be seen in FIG. 10 and aredescribed more fully below in connection with FIG. 11.

[0090]FIG. 11 illustrates a more detailed cross sectional side view ofconnector assembly 300 taken along line 11-11 in FIG. 10. As seen inFIG. 11, wire 307 includes both active potential supply wire 311 andshield monitor connection wire 314, which are split from wire 307 andconnected to active contact 310 and contact pins 212 respectively.Active contact 310 is held in place on plug floor 306 by active contactretaining pin 313.

[0091] Importantly, as shown in FIG. 11, contact pins 212 are surroundedby insulator cup 312 as shown. In the most preferred embodiment,insulator cup 312 is made from teflon, or other suitable elastomericinsulating material. Insulator cup 312 includes an upper cavity 318 inwhich shield monitor connection wire 314 is received and in whichconnection between shield monitor connection wire 314 and contact pins212 is made. Preferably, upper cavity 318 is filled with epoxy to secureshield monitor connection wire 314 and to protect the interconnectionbetween shield monitor connection wire 314 and contact pins 212.Additionally, plug cavity 320 is filled with silicon in order to protectand insulate the electrical connections therein.

[0092] Insulator cups 312 extend through floor 306 and include lowercavity 322 at an end opposite to upper cavity 318. The lower portion ofinsulator cups 312 has an outer diameter sufficient to achieve a tightfrictional fit with contact holes 214 shown in FIG. 9. In operation, itis important that this fit be sufficient to prevent moisture or othercontaminants from entering connector portion 14 through contact holes214. In this regard, lower cavity 322 is designed to flex inwardly tothe extent necessary to allow for insulator cup 312, and thereforecontact pins 212, to be tightly engaged with contact holes 214 andtherefore connector portion 14. To ensure a sufficiently tight fit, thelower portion of insulator cup 312 near lower cavity 322 may be made tohave a diameter slightly larger than that of contact holes 214 such thatthe lower portion of insulator cup 312 will flex into lower cavity 322during interconnection with connector portion 14. Also, the particularstructure of connector assembly 300 is such that a sealed attachmentbetween the connector assembly and the electrosurgical instrument occursin order to prevent breakdown between the shield and active electrodesof the electrosurgical instrument.

[0093] An alternative preferred embodiment of the present invention isshown in FIG. 12. The instrument shown in FIG. 12 differs fundamentallyfrom that shown in FIG. 3 in that the electrosurgical instrument shownin FIG. 3 includes an integral handle/shield/connector assembly intowhich articulatable inserts 20 having articulatable instruments 22attached thereto are selectively inserted, while the electrosurgicalinstrument shown in FIG. 12 includes an integral handle/articulatableinstrument assembly that is inserted through an integralshield/connector assembly.

[0094] Thus, as shown in FIG. 12, this alternative preferred embodimentof the electrosurgical instrument of the present invention includeshandle portion 402, active conductor 408 connected to handle portion402, and docking collar 404 surrounding a portion of active conductor408 and connected to handle portion 402. Furthermore, locking nut 410surrounds docking collar 404 and is longitudinally slidable with respectthereto from a point 412, where surface 414 of locking nut 410 contactssurface 416 of handle portion 402, to a point 418, where surface 420 oflocking nut 410 contacts surface 422 of docking collar 404. As describedin more detail below, this interaction between locking nut 410 anddocking collar 404 is particularly important in that it permits activeconductor 408 and the associated electrosurgical instrument (not shown)to be precisely positioned within the shield assembly. Locking nut 410is threadably received by connector portion 434 as indicated generallyat 411.

[0095] Although not shown in FIG. 12 for clarity, handle portion 402includes an appropriate user interface, such as illustrated in FIG. 3 byhandle assembly 12, which includes stationary handle 24 and movablehandle 26. Such user interface operates to slidably articulate anactuation rod disposed within the center of active conductor 408 tooperate an articulatable instrument disposed at an opposite end 424 ofthe electrosurgical instrument shown in FIG. 12. Together, handleportion 402, active conductor 408, docking collar 404 and locking nut410 form the integral handle/articulating instrument assembly inaccordance with this embodiment of the present invention.

[0096]FIG. 12 further depicts an integral shield/connector assemblyshown generally at 430. Integral shield/connector assembly 430 furthergenerally includes shield portion 432 and connector portion 434. FIG. 13shows an enlarged view of shield portion 432, which includes outerinsulating layer 436, shield 438 and inner insulating layer 440. In thisregard, it will be clear to one of skill in the art that the generalstructure of shield portion 432 is similar to that illustrated anddiscussed above in connection with FIG. 4.

[0097] As shown in FIG. 12, shield portion 432 is received intoconnector portion 434. Inner insulating layer 440 extends through aportion of connector portion 434 and is fastened to connector portion434 by compression ring 442. Outer insulating layer 436 extends intoconnector portion 434 to a lesser degree and is positioned with respectthereto by seal 444, which frictionally engages connector portion 434and outer insulating layer 436. Shield 438 extends into connectorportion 434 to a point between that of inner insulator 440 and outerinsulating layer 436 and is disposed within cavity 446 within connectorportion 434.

[0098] Connector portion 434 is constructed to allow for interconnectionto the shield 438 and active conductor 408 in a manner similar to thatdiscussed above in connection with FIGS. 8-11. Connector portion 434includes contact spring 450 that is similar in construction and functionto contact spring 210 shown in FIG. 9. Access to active conductor 408 isprovided in connector portion 434 by way of opening 452, which allowsactive contact 310 shown in FIGS. 10 and 11 to come into direct contactwith active conductor 408. Active contact electrode 120 is not necessaryin this embodiment of the present invention in that active conductor 408is formed to have an appropriate diameter to allow for directinterconnection of active contact 310 thereto.

[0099] Connector portion 434 also includes grommet 460 through whichactive conductor 408 is inserted and which cooperates with locking nut410 as shown. As is clear from FIG. 12, as locking nut 410 is threadedinto connector portion 434, grommet 460 will be forced into contact withactive conductor 408 and thus secure active conductor 408 in relation toconnector/shield assembly 430.

[0100] As discussed above, locking nut 410 surrounds docking collar 404and is longitudinally slidable with respect thereto from a point 412,where surface 414 of locking nut 410 contacts surface 416 of handleportion 402, to a point 418, where surface 420 of locking nut 410contacts surface 422 of docking collar 404. Accordingly, when engagedwith connector/shield assembly 430, it will be clear that handle portion402, active conductor 408 and docking collar 404 can be relativelypositioned with respect to connector shield assembly 430 and can besecured by tightening of locking nut 410 at any desired relativeposition. This feature is important in that any instrument, such asarticulatable instrument 22, may be selective exposed from end 424 ofshield portion 432. Accordingly, more or less of the electrosurgicalinstrument may be exposed depending on the particular surgical procedurebeing performed by the release of locking nut 410. From the forgoingdescription, it will be clear that the present invention providesnumerous improvements to shielded electrosurgical instruments. While themost preferred embodiment of the invention has been described in detail,it will be clear to one of skill in the art that the present inventionis not so limited.

What is claimed is:
 1. An articulating insert for use with a shieldedelectrosurgical instrument comprising: an articulating instrument formedon a first end of the articulating insert; connection means formed on asecond end of the articulating instrument; and securing means forsecuring said articulating instrument in the shielded electrosurgicalinstrument, said securing means operating to increase the rotationalforce necessary to remove the articulating insert from the shieldedelectrosurgical instrument relative to the force applied duringinsertion of the insert.
 2. The articulating insert of claim 1 whereinsaid securing means includes a housing having a first surface thatengages a second surface of the electrosurgical instrument at an outerperiphery thereof, said first surface being formed at a first angle,said first angle being less than ninety degrees from the longitudinalsurface of the articulating insert.
 3. The articulating insert of claim2 wherein said second surface of the electrosurgical instrument isformed at a second angle, said second angle being less than ninetydegrees from the longitudinal surface of the articulating insert.
 4. Thearticulating insert of claim 3 wherein said first angle is less thansaid second angle.